There are two main routes to reinstalling Windows XP on an individual PC:

Using a Manufacturer's System Restore CDs

Using a Microsoft Windows Installation CD

Which you follow will normally be determined by what CDs (if any) were provided with your computer. If you have neither of these available, you could try contacting the machine's manufacturer or supplier.

Please note that IT Services can only supply Windows (upgrade) CDs for use on University of staff-owned machines.

In some cases, a manufacturer may have placed a copy of the Windows installation CD contents in a folder on your machine's hard disk, typically located at c:\windows\options\cabs. If you are in this situation and are able to transfer the conents of this folder to a CD, then this could provide you with a suitable re-installation source, although you might also need a separate Windows boot CD or floppy disk. If you do not have such a disk, you may be able to create one via http://www.bootdisk.com.

1. Manufacturer's System Restore CDs

Many machines, particularly laptops, are now supplied with one or more System Restore CDs. These are different from Microsoft Windows Installation CDs and are designed to restore your system to exactly how it was when it left the factory. Use of System Restore CDs will completely destroy any other software and documents you have installed or created on the machine since it was new. A separate document contains information on how to make a back up of your own data files. To reinstall applications such as Microsoft Office, you will need to have your own copy of the original installation media for each program.

Instructions for use of the CDs should be in your machine's documentation. This normally involves booting the machine from a System Restore CD and following the onscreen instructions. This should be done with the machine disconnected from the network.

After using Sytem Restore CDs, you should install any Windows XP service packs later than the ones included on the CDs. If you are installing Windows XP Service Pack 2, you should do this from a CD rather than by online download (your local IT staff should have a CD for this). Connecting to the network (even for a few seconds) without having reinstalled Windows service packs will immediately expose you to external attack. You should also install up-to-date antivirus software before connecting to the network.

Finally, you can reinstall all the applications for which you have installation media, and also restore your own data and document files.

2. Microsoft Windows XP Installation CD

This procedure will completely wipe your hard disk and install a fresh copy of Windows. You will then need to reinstall all your application programs from their original CDs, and to restore your own files from whatever backup copies you have previously made.

If your Windows CD is an upgrade version (it should say this on the CD) you will need to have a CD from some earlier Windows version available during the installation process.

Reinstalling Windows should be done with your computer disconnected from the network.

To reinstall Windows XP completely:

Start up your machine from the Windows CD. On most modern machines, simply turn off your computer, insert your Windows CD into the CD-Rom drive, and restart your computer. Some computers require you to press a key to boot from a CD - if so, there will normally be an onscreen message to this effect. If the Windows setup does not begin, you may need to change the system's BIOS settings accessed at power up by pressing a particular key. The BIOS "Boot Options" need to be configured to try and boot from a CD.

At the Welcome to Setup screen, press ENTER to start Windows XP Setup.

Read the End-User License Agreement, and then press F8.

Follow the instructions on the screen to select and format a partition where you want to install Windows XP.

Follow the instructions on the screen to complete Windows XP Setup. During the setup process, you will have the option of formatting your hard drive; choose that option to erase your damaged/hacked Windows installation, and proceed with the reinstall.

Once Windows has been reinstalled, you should:

Install current service packs, preferably from a CD - your local IT staff should be able to povide this. You should not reconnect to the network until this has been done.

Reinstall your other programs individually from your original install disks.